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CVE.org (no NVD analysis yet)· CNA Vaadin

CVE-2026-120326: Unescaped Download File Name Allows Content-Disposition Parameter Injection in Vaadin Flow

MediumCVSS 4.8 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 19/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
  • Fixed version: vaadin flow 24.10.17, 24.9.31, 25.2.16; vaadin vaadin 24.10.14, 24.9.26, 25.2.13; vaadin vaadin-core 24.10.14, 24.9.26, 25.2.13.

Low priority for now. Upgrade to vaadin flow 24.10.17, 24.9.31, 25.2.16; vaadin vaadin 24.10.14, 24.9.26, 25.2.13; vaadin vaadin-core 24.10.14, 24.9.26, 25.2.13 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

DownloadEvent.setFileName(String) in Vaadin Flow writes the download file name into the Content-Disposition header without escaping it. When the name is pure US-ASCII the header is built as attachment; filename="<name>" with the name inserted verbatim, so a double quote in the name ends the quoted string early and the rest of the name is read by the browser as further header parameters. The inline(String) variant, present from Vaadin 25.0, builds the name the same way. An application that passes an untrusted file name to either method, for example when re-serving a file under the name it was uploaded with, lets an attacker add a filename* parameter. Browsers prefer filename* over filename, so the file is saved under a name and extension of the attacker's choosing, which defeats any file name or extension restriction the application enforces. The attacker cannot change the attachment or inline disposition itself and cannot split the header. Users of affected versions should apply the following mitigation or upgrade. Releases that have fixed this issue include: Product version Vaadin 24.8.0 - 24.8.17 Vaadin 24.9.0 - 24.9.25 Vaadin 24.10.0 - 24.10.13 Vaadin 25.0.0 - 25.0.13 Vaadin 25.1.0 - 25.1.13 Vaadin 25.2.0 - 25.2.12 Vaadin 25.3.0 - 25.3.4 Mitigation No fixed release on this line, upgrade to 24.9.26 or newer Upgrade to 24.9.26 Upgrade to 24.10.14 No fixed release on this line, upgrade to 25.2.13 or newer No fixed release on this line, upgrade to 25.2.13 or newer Upgrade to 25.2.13 Upgrade to 25.3.5 Vaadin versions below 24.8 are not affected: the DownloadEvent API does not exist in them.

Published
Nov 10, 2026
Updated
Nov 10, 2026
EPSS
0.2% · 14th percentile

Report tools

JSON

Action score

19

Monitor

Low priority for now.

CVSS
19 / 40 · 4.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CNA vs NVD score

NVD
—
CNA · Vaadin
4.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-120326

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Vaadin). Independent of NVD's CPE analysis and usually ahead of it.

  • vaadin flow

    • 24.8.0 and later · up to and including 24.8.16affected · maven
    • 24.9.0 and later · before 24.9.31affected · maven
    • 24.10.0 and later · before 24.10.17affected · maven
    • 25.0.0 and later · up to and including 25.0.15affected · maven
    • 25.1.0 and later · up to and including 25.1.19affected · maven
    • 25.2.0 and later · before 25.2.16affected · maven
    • 25.3.0 and later · before 25.3.6affected · maven

  • vaadin vaadin

    • 24.8.0 and later · up to and including 24.8.17affected · maven
    • 24.9.0 and later · before 24.9.26affected · maven
    • 24.10.0 and later · before 24.10.14affected · maven
    • 25.0.0 and later · up to and including 25.0.13affected · maven
    • 25.1.0 and later · up to and including 25.1.13affected · maven
    • 25.2.0 and later · before 25.2.13affected · maven
    • 25.3.0 and later · before 25.3.5affected · maven

  • vaadin vaadin-core

    • 24.8.0 and later · up to and including 24.8.17affected · maven
    • 24.9.0 and later · before 24.9.26affected · maven
    • 24.10.0 and later · before 24.10.14affected · maven
    • 25.0.0 and later · up to and including 25.0.13affected · maven
    • 25.1.0 and later · up to and including 25.1.13affected · maven
    • 25.2.0 and later · before 25.2.13affected · maven
    • 25.3.0 and later · before 25.3.5affected · maven

Same product

vaadin: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-107588Multiple Vulnerabilities in the Highcharts Library Bundled with Vaadin Charts
    33Monitor
  • CVE-2021-31409Server session is not invalidated when logout() helper method of Authentication module is used in Vaadin 18-19
    31Monitor
  • CVE-2020-36320Regular expression Denial of Service (ReDoS) in EmailValidator class in Vaadin 7
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-93547Sep 30, 2026 · Missing Authorization Check in Vaadin Spreadsheet Allows Cell Comments to Be Written to Protected Sheets and Locked Cells
    21Monitor
  • ← EarlierCVE-2026-110737Oct 27, 2026 · Push Endpoint Returns Permissive CORS Headers
    9Monitor
  • Later →CVE-2026-120350Nov 10, 2026 · Stored Cross-Site Scripting in the Vaadin Rich Text Editor via an Unescaped Video Embed
    20Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
vaadin flow24.10.17Vendor (CNA)
vaadin flow24.9.31Vendor (CNA)
vaadin flow25.2.16Vendor (CNA)
vaadin flow25.3.6Vendor (CNA)
vaadin vaadin24.10.14Vendor (CNA)
vaadin vaadin24.9.26Vendor (CNA)
vaadin vaadin25.2.13Vendor (CNA)
vaadin vaadin25.3.5Vendor (CNA)
vaadin vaadin-core24.10.14Vendor (CNA)
vaadin vaadin-core24.9.26Vendor (CNA)
vaadin vaadin-core25.2.13Vendor (CNA)
vaadin vaadin-core25.3.5Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+3 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
A
Scope
X

Weakness class (CWE)

CWE-116 · Improper Encoding or Escaping of Output

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

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References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records